As is known, integrated circuits are used in a wide variety of electronic equipment, including portable, or handheld, devices. Such handheld devices include personal digital assistants (PDA), CD players, MP3 players, DVD players, AM/FM radio, a pager, cellular telephones, computer memory extension (commonly referred to as a thumb drive), etc. These handheld devices include one or more integrated circuits to provide the functionality of the device. For example, a thumb drive may include an integrated circuit for interfacing with a computer (for example, personal computer, laptop, server, workstation, etc.) via one of the ports of the computer (for example, Universal Serial Bus, parallel port, etc.) and at least one other memory integrated circuit (for example, flash memory). As such, when the thumb drive is coupled to a computer, data can be read from and written to the memory of the thumb drive. Accordingly, a user may store personalized information (for example, presentations, Internet access account information, etc.) on his/her thumb drive and use any computer to access the information.
As another example, an MP3 player may include multiple integrated circuits to support the storage and playback of digitally formatted audio (that is, formatted in accordance with the MP3 specification). As is known, one integrated circuit may be used for interfacing with a computer, another integrated circuit for generating a power supply voltage, another for processing the storage and/or playback of the digitally formatted audio data, and still another for rendering the playback of the digitally formatted audio.
Integrated circuit technology has led to a plethora of handheld devices; however, to be “wired” in today's electronic world, multiple handheld devices would be needed. For example, one may own a cellular telephone for cellular telephone service, a PDA for scheduling, address book, etc., one or more thumb drives for extended memory functionality, an MP3 player for storage and/or playback of digitally recorded music, a radio, etc. Thus, even though a single handheld device may be relatively small, carrying multiple handheld devices on one's person can become quite burdensome.
Such handheld devices use a battery (or batteries) to supply power to the circuitry of the device. The greater the circuit power consumption, the shorter the battery life (that is, the length of time a device can be operated before having to replace or charge the battery).
With the goal of extending battery lifespan for portable devices, various techniques had been used. One technique has been to turn off circuitry that is not needed to support the present function and to put the device in a “sleep” mode when the entire device is not in use.
Another technique is related to improvements in integrated circuit fabrication that allows for smaller devices to be developed and to be operated at lower voltages, thus consuming less power. For example, 0.18 micron Complementary Metal Oxide Semiconductor (“CMOS”) integrated circuit technology is currently the most accepted process, which uses supply voltages of 1.8 volts. Several years ago, however, 0.35 micron and 0.50 micron CMOS integrated circuit technologies were the prevalent processes, which could use supply voltages of about 3.3 volts. In the near future, 0.10 and 0.13 micron CMOS integrated circuit technology will likely become the technology of choice because of lower supply voltages of about 1.0 volts.
While these design techniques worked to reduce power consumption generally, they had been designed assuming the worst-case operation of an integrated circuit. As such, integrated circuit circuits would be consuming more power than needed because the power reducing techniques were under a worst-case assumption and not individually optimized on a chip-by-chip basis.
Generally, digital components and analog components are operated under different processes, techniques, or parameters for their desired functional results. Because digital component operation is based on clock speed, and analog component operation is based on bias factors such as threshold voltage, different operational parameters or conditions may be more favorable for one over the other. For example, lower operational temperatures raise the threshold voltage level for analog components, affecting signal performance, while favorable for digital component operation. Conversely, higher operational temperatures lower the threshold voltage level for analog components, while slowing digital gate response for digital components. Accordingly, power consumption considerations for each type of component would differ.
Therefore, a need exists for an integrated circuit that provides multiple functions through mixed-signal operation and architectures for handheld devices with appropriate optimized power-consumption and with a minimal requirement of external components.